More than 100 square miles of backcountry in Alaska's Denali National Park remains under emergency closure after a hiker was mauled to death by a grizzly bear on Friday. It's the only fatal bear attack in the park's 90-year history. Forty-nine-year-old Richard White of San Diego - a solo backpacker - had been photographing the bear for some eight minutes before he was killed. Other hikers found his backpack and bloodied clothing, and alerted park rangers. A wildlife trooper shot and killed the bear on Sunday, and rangers recovered Mr. White's remains.

Paul Anderson is Denali Park's superintendent and he joins me talk about what happened. Paul Anderson, welcome to the program.

PAUL ANDERSON: Thank you.

BLOCK: You've been able to document the time leading up to this fatal attack, because you recovered Mr. White's camera. What do those images show?

ANDERSON: There's a number of images that are time-stamped on his camera and they show the bear acting normally, grazing in the edge of the river for about seven minutes of time that he was taking photographs. And he took a number of photographs of the bear. In the last minute of the photographs, the bear turned towards him and approached him very closely.

BLOCK: Could you tell anything from the pictures, those last pictures, about the bear's demeanor?

ANDERSON: Well, certainly, it was - it could be characterized either as curious or aggressive. But he wasn't charging him at the time that the last picture was taken. He was just walking deliberately towards him.

BLOCK: I've read that Mr. White was about 50-yards away from the grizzly bear when he was killed. How fast could a grizzly cover that distance?

ANDERSON: If the grizzly were running at top speed it would just be a matter of seconds.

BLOCK: A matter of seconds. And hikers there are told to stay how far from a grizzly bear?

ANDERSON: The regulation distance between the hiker and the bear is a quarter mile.

BLOCK: And Mr. White had some kind of bear awareness training before he set out?

ANDERSON: He did have bear awareness training before he went out. He had a backcountry permit and bear awareness training is a required part of issuing that backcountry permit.

BLOCK: I'm curious about this - I mentioned that the bear was shot and killed. It was a male, 600 pounds. At the point that it was shot, it was clear that Mr. White was dead. Is it park policy to kill a bear after an attack like this? Why would the bear be killed?

ANDERSON: The park as a bear management plan. If a bear were only to attack a visitor and maul them, not kill them, and then back off and leave the area,we would monitor the bear. We wouldn't dispatch it. But the plan is fairly clear. When a bear attacks a person and then identifies it as a food source and, as in this case, he killed the person out on the gravel bar and then dragged him 150 yards into the brush where he partially buried him after having fed upon him for a period of time and then sat on that cache and wouldn't allow any other animals or humans to approach them without a fear of attack.

BLOCK: So this killing indicates something about possible future behavior?

ANDERSON: There have been documented incidents in the past, in other parks in the country, of bears that kill hikers or backpackers or people in the park and then feed upon them, continuing to do so. And we're not prepared to take that kind of risk here at Denali, given the proximity to hundreds of thousands of visitors.

BLOCK: I imagine that a killing like this must take a real toll on the staff there.

ANDERSON: Certainly. I guess the thing that's most important here is that, as I was talking to some of the wildlife people, when you deal with bears every day and you get to know their behavior, familiarity can sometimes breed a lack, or a reduced awareness of what's possible. And, I mean, I think there's a lot of people here that are at the moment are rethinking how careful they are as they travel in the backcountry and work with the wildlife.

BLOCK: Well, Paul Anderson, thank you for talking with us today.

ANDERSON: Thank you.

BLOCK: Paul Anderson is the superintendent of Denali National Park. The hiker, Richard White, is survived by a wife and young daughter. His father told the San Diego Union Tribune: He had a real zest for seeing the phenomena in the world. He enjoyed being out in the wilderness. Transcript provided by NPR, Copyright NPR.